Radon gas is a natural radioactive gas that you can't see, smell or taste [1]. Iowa's state brochure says it comes from the decay of uranium in the soil, and that breathing its decay products can damage the lungs [2]. Iowa has some of the highest levels in the country, which is why state and county health offices push testing.
How it gets in
Iowa HHS's brochure lists cracks in the foundation, construction joints, gaps around pipes or wires, and sump pits [2]. Linn County Public Health adds private wells, groundwater and gaps in suspended floors [3]. The brochure says foundation type doesn't matter. Homes with a basement, crawl space or slab can all have high levels [2].
Iowa's numbers
- Every county is Zone 1. EPA's county list places all 99 Iowa counties in Zone 1 [4]. A 2020 state fact sheet explains that Zone 1 counties have a predicted average indoor screening level above 4 pCi/L [5].
- Most homes test high. Iowa HHS says the Iowa Radon Survey found 71.6% of homes above 4 pCi/L, the largest share of any state [6].
- High averages. The fact sheet gives an Iowa indoor average of 8.5 pCi/L against 1.3 nationally [5]. The brochure says Iowa leads the nation in the share of homes over 4 pCi/L and over 20 pCi/L [2].
- House to house. Levels can differ a lot between homes on the same street [5].
EPA says its zone map should not be used to decide whether an individual home needs a test [4]. Test anyway.
The health risk
Iowa HHS, citing EPA, says radon is the leading cause of lung cancer in nonsmokers and the second leading cause in smokers [1]. EPA's citizen's guide puts radon at about 21,000 lung cancer deaths a year in the U.S., based on its 2003 risk assessment [7]. The state fact sheet says EPA estimates about 400 deaths a year in Iowa from long-term exposure [5].
Local help
- Statewide: the Iowa radon hotline, run for Iowa HHS by the American Lung Association, at 1-800-383-5992, 8:30 a.m. to 4:30 p.m. Central [1].
- Linn County Public Health: kits and a results chart, 319-892-6000 [3].
- Johnson County Public Health: kits, 319-356-6040 [8].
Iowa's rules for testers and mitigation specialists are on how it works. For kits, see radon test kits.
FAQ
If my neighbor's house tested low, am I fine?
No. The state fact sheet says homes right next to each other can have high and low levels [5].
Is radon in water a concern?
EPA says radon coming in from soil is a much larger risk than radon from water, and to test the air first [9].
Get a quote
We're a referral service, not a contractor. We send mitigation requests only to contractors on Iowa HHS's current credentialed list and testing requests only to state-certified radon measurement specialists, but we don't otherwise vet them, a referral is not an endorsement, and independent contractors may pay us for referrals.
Sources
- Iowa HHS, Radon program page (fetched Nov 11, 2026). https://hhs.iowa.gov/health-prevention/providers-professionals/radiological-health/radon
- Iowa HHS, Radon & You: What you need to know to protect you and your family (brochure PDF, fetched Nov 11, 2026). https://hhs.iowa.gov/media/7880/download?inline
- Linn County Public Health, Radon (fetched Nov 11, 2026). https://www.linncountyiowa.gov/1747/Radon
- U.S. EPA, EPA Map of Radon Zones, last updated Aug 17, 2026. https://www.epa.gov/radon/epa-map-radon-zones
- Iowa HHS (as IDPH), Iowa Radon Home Buyers and Seller Fact Sheet, dated 2/2020 (PDF). https://hhs.iowa.gov/media/7917/download?inline
- Iowa HHS, Radon Resources (fetched Nov 11, 2026). https://hhs.iowa.gov/health-prevention/providers-professionals/radiological-health/radon/radon-resources
- U.S. EPA, A Citizen's Guide to Radon, EPA 402/K-12/002 (2025 edition, PDF). https://www.epa.gov/sites/default/files/2016-12/documents/2016_a_citizens_guide_to_radon.pdf
- Johnson County Public Health, Radon Information (fetched Nov 11, 2026). https://www.johnsoncountyiowa.gov/public-health/radon
- U.S. EPA, Home Buyer's and Seller's Guide to Radon, EPA 402/K-24/001 (revised March 2024, PDF). https://www.epa.gov/sites/default/files/2015-05/documents/hmbuygud.pdf